Playback session

This sample application demonstrates how to use audio APIs for a playback session.

1. Get the AudioFactory instance

auto &audioFactory = AudioFactory::getInstance();

2. Get the AudioManager instance and check for audio subsystem readiness

std::promise<ServiceStatus> prom{};
// Get the AudioManager instance
audioManager = audioFactory.getAudioManager([&prom](ServiceStatus serviceStatus) {
    prom.set_value(serviceStatus);
});
if (!audioManager) {
    std::cout << "Failed to get AudioManager instance" << std::endl;
    return;
}

// Check if audio subsystem is ready
// If audio subsystem is not ready, wait for it to be ready
ServiceStatus managerStatus = audioManager->getServiceStatus();
if (managerStatus != ServiceStatus::SERVICE_AVAILABLE) {
    std::cout << "\nAudio subsystem is not ready, Please wait ..." << std::endl;
    managerStatus = prom.get_future().get();
}

// Check the audio service status again
if (managerStatus == ServiceStatus::SERVICE_AVAILABLE) {
    std::cout << "Audio Subsytem is Ready << std::endl;
} else {
    std::cout << "ERROR - Unable to initialize audio subsystem" << std::endl;
    return;
}

3. Create an audio playback session

// Callback which provides response to createStream, with pointer to base interface IAudioStream
 void createStreamCallback(std::shared_ptr<IAudioStream> &stream, ErrorCode error)
 {
     if (error != ErrorCode::SUCCESS) {
         std::cout << "createStream() returned with error " << static_cast<int>(error)
             << std::endl;
         return;
     }
     std::cout << "createStream() succeeded." << std::endl;
     audioPlayStream = std::dynamic_pointer_cast<IAudioPlayStream>(stream);
 }

 // Create an audio stream
 StreamConfig config;

 config.type = StreamType::PLAY;
 config.sampleRate = 48000;
 config.format = AudioFormat::PCM_16BIT_SIGNED;
 config.channelTypeMask = ChannelType::LEFT;
 config.deviceTypes.emplace_back(DeviceType::DEVICE_TYPE_SPEAKER);

 status = audioManager->createStream(config, createStreamCallback);

4. Allocate stream buffers for playback operation

// Get an audio buffer (we can get more than one)
auto streamBuffer = audioPlayStream->getStreamBuffer();
if (streamBuffer != nullptr) {
    // Setting the size that is to be written to stream as the minimum size
    // required by stream. In any case if size returned is 0, using the Maximum
    // Buffer Size, any buffer size between min and max can be used
    size = streamBuffer->getMinSize();
    if (size == 0) {
        size =  streamBuffer->getMaxSize();
    }
    streamBuffer->setDataSize(size);
} else {
    std::cout << "Failed to get Stream Buffer " << std::endl;
}

5. Start write operation for playback to start

// Callback which provides response to write operation
void writeCallback(std::shared_ptr<IStreamBuffer> buffer, uint32_t size, ErrorCode error)
{
    if (error != ErrorCode::SUCCESS) {
        std::cout << "write() returned with error " << static_cast<int>(error) << std::endl;
    } else {
        std::cout << "Successfully written " << size << " bytes" << std::endl;
    }
    buffer->reset();
    return;
}

// Write desired data into the buffer
// Very first write starts the playback session
memset(streamBuffer->getRawBuffer(),0x1,size);

auto status = audioPlayStream->write(streamBuffer, writeCallback);
if(status != telux::common::Status::SUCCESS) {
    std::cout << "write() failed with error" << static_cast<int>(status) << std::endl;
} else {
    std::cout << "Request to write to stream sent" << std::endl;
}

6. Dispose the audio stream

// Callback which provides response to deleteStream
void deleteStreamCallback(ErrorCode error) {
    if (error != ErrorCode::SUCCESS) {
        std::cout << "deleteStream() returned with error " << static_cast<int>(error)
            << std::endl;
        return;
    }
    std::cout << "deleteStream() succeeded." << std::endl;
    audioPlayStream.reset();
}

// Delete the audio stream
Status  status = audioManager->deleteStream(
           std::dynamic_pointer_cast<IAudioStream>(audioPlayStream), deleteStreamCallback);
if (status != Status::SUCCESS) {
    std::cout << "deleteStream failed with error" << static_cast<int>(status) << std::endl;
}